Fix representation

It might be just me, but with `unless` it sounds like **if you want to use your forms in multiple places you should define it in your controllers**.


| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3
| Fixed tickets |

Author: ifdattic

best_practices/forms.rst

@@ -13,7 +13,7 @@ Building Forms
     Define your forms as PHP classes.
 
 The Form component allows you to build forms right inside your controller
-code. Honestly, unless you need to reuse the form somewhere else, that's
+code. Honestly, if you don't need to reuse the form somewhere else, that's
 totally fine. But for organization and reuse, we recommend that you define each
 form in its own PHP class::